When someone tells you to get real, they want you to get a reality check and to stop behaving as though you're living in a fantasy world.
Could apply to pretty much anyone or anything (as in a company or organisation) that mentally is not living in reality.
Examples can include companies paying their employees minimum wage while demanding preformance and duties etc that someone willing to preform them is worth at least twise that. On the other side of the coin, it can also include employees demanding pay that is far in excess of what the company can realistically afford to pay them.
Basically anyone or anything that expects something that just isn't realistic, saying 'get real' means to tell them to stop being unrealistic.

Employee: I demand $75,000 a year, a company car, 50,000 shares of the company's stock, every benifit imaginable and a months vacation every year to start.
Interviewer: Get real, this is a burger flipping job, not an executive job.

Getting real is the act of giving yourself a reality check. If a person is trying to convince you of something unrealistic, you tell them to "Get Real." Get Real is also a title that you can earn in Call of Duty Modern Warfare 2 by winning one match of Hadcore Team Deathmatch.

1. You honestly play hardcore teamdeathmatch? You need to get real.

2. Eric: Dylan, why are you lying prone camping in spawn

Dylan: Because its a good strategy and I'm worried about my kill to death ratio.

Eric:Dylan, seriously you need to get real. You need to sack up and attack like the rest of us.

When a humorous situation has the potential to become much more serious. Many funny things such as pranks can "Get Real" in a short matter of time. Let's say you are performing a prank where you lube up the floor for your roommate to slip and fall. You wait for you roommate to enter the room, they slip and break their nose, arm, and neck. hmmm.. this prank didn't turn out to be as funny as once expected now did it? Now you have to take them to the hospital, and clean up the slippery floor when you get back home.
Plus now there's legal stuufff, and all these rumors around the neighborhood about you being a total douche and all....
Geeeez.. should have read up on the Urban Dictionary definitions first!

Zachary- "Ha Ha! this nail in the road prank is absolutely hilarious to watch! And everyone here is accepting me socially because I put the nail in the road and cars are getting really close to running it over!"

Ryan- "Yes the prank is fun to watch for now, but when a car really does blow a tire this is going to Get Real."